This invention relates generally to a novel apparatus providing variable speed control of cams in textile machines to prevent bunching of threads, especially during relatively high speed winding. More particularly, this invention concerns an apparatus providing for the control of cams in a textile machine by a motor in mechanical communication with the cams. The motors which control the cams vary, according to a predetermined cycle, the speed of the textile machine cams. Preferably, two motors are arranged with a common induction source which fixes the motors' average speeds and exchanges the motors' braking energy. The speed variations around the average speed of the motors is modulated in phase opposition by the variation in flux in each motor which thereby produces a staggering of the thread spools from one layer to the other and avoids formation of bunches on the formed winding.
The apparatus has utility in relatively high speed textile machines for texturation by false torsion.
It is well known in the art that in the winding of threads upon spools of textile machines, it is imperative that the speed of the conventional moving devices which distribute the thread on the spools be varied in order to avoid bunching of the threads. Bunching is a problem recognized in the art involving the avoidance of having the thread spirals superimposed one on top of the other.
In the past, mechanical mixers or variators have been used which modulate the average speed of rotation for the cam feed devices with periodic symmetric signals (for example, a triangle signal). Accelerating and periodically braking the speed of the feed devices which distribute the threads is necessary.
Prior art arrangements have been unsatisfactory in relatively high speed textile machines. Modern textile machines are capable of winding speeds which are appreciably faster than may be satisfactorily accomodated by typical prior art devices. The unsatisfactory prior art devices are particularly lacking in the case of, for example, textile machines for the texturation by false torsion, where in recent years, such machines have been capable of winding speeds of 400 meters per minute to 1,000 meters per minute.
While prior art arrangements have exhibited a degree of utility in older and slower textile machines, room for significant improvement remains.